1. Field of the Invention
This invention relates to silver halide light-sensitive materials, and, more particularly, to silver halide photographic light-sensitive materials wherein static buildup is reduced and the components thereof are transferred in only negligible small amounts to a transport roll or a fluorescent intensifying screen for X-ray photography (hereinafter referred to simply as a "screen").
2. Description of the Prior Art
Static buildup on photographic sensitive materials has long annoyed the photographic industry. Static electricity may be generated during the manufacture and use of photosensitive materials when they are wound on rolls, rewound therefrom, transported on rollers or when they contact other objects in transit. Generation and accumulation of static charges is a product of, for example, the electric conductivity and triboelectric characteristics of the photographic material, moisture, the properties of the contacted object, and the atmosphere in which the contact occurs. Accumulated static electricity sometimes discharges to cause irregular fogging of the photosensitive material. This is so deleterious to the material that it may even completely lose its commercial value. For instance, an X-ray film, even if it experiences the slightest fogging, not only fails to achieve the intended purpose but may result in an inaccurate diagnosis.
It is well known to provide an antistatic layer in a photographic material so as to avoid any adverse effect of static buildup, and many types of photographic materials have been proposed that incorporate an antistatic layer that dissipates static charges. Illustrative examples include U.S. Pat. Nos. 2,649,374, 3,033,679, 3,437,487, 3,525,621, 3,630,740, and 3,681,070, Japanese Patent Publication No. 4380/73 and Japanese patent application (OPI) No. 113221/75 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"). These references describe various antistats and antistatic layers that contain them. However, these conventional antistatic (antistat) agents or antistatic layers have various serious defects that make them less than totally suitable for use as a component of a photographic sensitive material. For example, due to insufficient antistatic properties, they may be unable to prevent fogging from occurring in a high-sensitivity photographic material; or, the antistatic layer may dissolve in a developing bath to form scum; or, the layer or the photographic material that contains it may be so low in strength that it becomes less abrasion-resistant and durable to the extent that it is no longer of value as a commercial product or may create problems in the production thereof.
To let a certain compound achieve the intended effect as an antistat, it is generally required that the compound be incorporated in a photographic light-sensitive material in a greater amount that when it is used for other purposes, (for example, as a coating aid, emulsifying agent, or sensitizing agent). This is presumably because an antistat must form a continuous layer in order to remain electrically conductive in a photographic layer. However, when the antistat is used in a great amount, much of it remains on the surface of a photosensitive material, causing various problems in the preparation or use of the photosensitive material, since it may be transferred to transport rollers, a camera or screen that contact the surface of the material. For instance, an antistat transferred to a transport roll may stain the roll, and the stain may be deposited on a film that subsequently passes between the rolls. If the antistat is transferred to a screen, the characteristics of the screen may be changed, or a stain or blur may be formed on the X-rayed photographic material. This not only impairs the product quality but may result in an inaccurate diagnosis.